Free Republic
Browse · Search
News/Activism
Topics · Post Article

To: Timocrat

Depends on lots of things at that point.

When the main engines fail, there’s an APU (aux. power unit) that’s a little turbine/genset that is supposed to start to maintain electrical and hydraulic power for the flight control systems. Eventually, that’s going to run out of fuel as well.

In the Boeing heavies, then a RAT (Ram Air Turbine) drops out of the underside of the jet to provide emergency electrical and hydraulic power for the control systems and surfaces. Even with no fuel, the plane’s engineers planned for allowing control of these “fly by wire” systems.

The problem is that the optimum glide speed is “moving right along” in these heavy jets. We’re talking over 200 knots - perhaps as high as 240 knots airspeed. Their glide ratios are over 15:1 (typically) and they’re losing altitude at a pretty good clip (3000 to over 4500 feet per minute) to maintain an optimum glide speed and flight profile.

This ain’t like losing the engine in a Cessna 172 and gliding it down to the airstrip, flaring in the ground effect and kicking in a little crosswind rudder to line ‘er up on the runway. Pilots can and have glided Boeing heavies into a successful landing on even improvised airstrips - so Boeing heavies do glide successfully. In this case, however, we don’t know if there was a pilot at the controls, or a pilot who wanted to live, or what. All I meant with the above comment is that if the 777 went into the sea at a high speed and high angle, the debris field is likely to be quite limited. Look at what happened to the hijacked Flight 93 that was deliberately flown into the ground at a high angle in PA - there was actually little surface disturbance and a very small amount of debris above ground:

http://www.slimyfish.net/images/blog/flight93.jpg


61 posted on 03/24/2014 1:07:54 PM PDT by NVDave
[ Post Reply | Private Reply | To 49 | View Replies ]


To: NVDave

Just had a thought while outside picking up some glass from small greenhouse that was suppose to be shatterproof
I know the glass in the cockpit is very strong. What would it take to break it?


64 posted on 03/24/2014 1:17:16 PM PDT by hoosiermama (Obama: "Born in Kenya" Lying now or then or now)
[ Post Reply | Private Reply | To 61 | View Replies ]

To: NVDave
there was actually little surface disturbance and a very small amount of debris above ground:

Wow that picture is amazing, never realized it had such a small impact zone. Presumably there would be more of the aircraft left hitting water than dry land, especially in a part of the ocean where there is usually a turbulent swell.

68 posted on 03/24/2014 1:32:27 PM PDT by Timocrat (Ingnorantia non excusat)
[ Post Reply | Private Reply | To 61 | View Replies ]

Free Republic
Browse · Search
News/Activism
Topics · Post Article


FreeRepublic, LLC, PO BOX 9771, FRESNO, CA 93794
FreeRepublic.com is powered by software copyright 2000-2008 John Robinson